1. Field of the Invention
The present invention relates in general to household or xe2x80x9cbathroomxe2x80x9d scales and in particular to such scales which include a rigid, decorative foot mat that strengthens the upper housing of a scale.
2. Description of Prior Developments
Scales of the type known as household or xe2x80x9cbathroomxe2x80x9d scales typically include a lower housing or base and an upper housing or cover. These components are typically formed of stamped sheet metal and interconnected by coil springs. In order to provide an economical assembly, the sheet metal used to form the base and cover is typically constructed of relatively thin gauge material.
As a result, the cover is frequently reinforced with one or more panels or braces which underlie, support and rigidify the cover. While this approach proves satisfactory from a structural standpoint, it complicates the assembly of the cover and adds to its cost. Accordingly, a need exists for a strong, rigid scale cover which has a relatively simple construction, yet can be fabricated from a relatively thin gauge sheet metal.
Another issue associated with bathroom scale designs is the need to provide an exterior platform surface for securely supporting a user""s feet during weighing. These surfaces are typically covered with a rubber or vinyl pad or mat to reduce slipping. The mats are generally glued to the underlying sheet metal platform with an adhesive.
Unfortunately, the adhesive often fails to hold the corners and edges of the mats in place and, over time, results in an unsightly scale platform having a mat with loose curled edges. Accordingly, a need exists for a covering for the platform of a bathroom scale which is permanently attached to the scale platform so as to eliminate the occurrence of loose curled edges, and avoid the use of adhesives.
Another issue associated with scale mats is their appearance. Attempts have been made to enhance the appearance of bathroom or household scales by applying secondary finishes to the scales in order to simulate natural materials such as stone, granite, marble, jade, etc. These finishes increase the cost of the scale and can be difficult to apply correctly.
Mounting of slabs, mats, or panels of natural material on the scale platforms incurs significant material cost. Additional costs are incurred in the labor required to fabricate and attach the mats to the scale platforms.
Accordingly, a further need exists for a bathroom or household scale which has an exterior surface that can realistically and economically simulate natural materials of the type noted above. A further need exists for such a material that can be readily formed with a textured surface to improve the grip between the scale and a user""s feet.
The present invention has been developed to fulfill the needs noted above, and therefore has as an object the provision of a bathroom scale having a rigid platform weighing surface constructed of relatively thin gauge sheet metal.
Another object of the invention is the provision of a bathroom scale having a weighing surface covered with a rigid mat which is permanently attached to the weighing surface, and incapable of curling and peeling away from the weighing surface.
Another object of the invention is the reduction or elimination of internal braces and supports for supporting a weighing surface or platform of a household or bathroom scale.
Yet another object of the invention is the provision of a rigid textured mat on the weighing surface or platform of a scale which can provide a high friction surface and also structurally reinforce the underlying sheet metal cover of the scale.
Still another object of the invention is the provision of a rigid foot rest or foot mat which overlies a scale cover and which can be molded as a rigid plastic panel or sheet having various colors, textures and patterns resembling natural materials such as marble, jade and stone.
Another object of the invention is the provision of a high strength molded plastic mat which is highly resistant to impact damage and avoids the need for adhesives.
These and other objects are met by the present invention which is directed to a bathroom or household scale having a weighing platform covered with one or more rigid plastic mats or panels. The mats are molded with mounting projections such as pegs which align with and are inserted within mounting holes formed in the weighing surface or platform portion of the scale cover. In this case, the scale cover can be fabricated from relatively thin gauge sheet metal, yet accommodate heavy loads due to the structural support provided by the relatively rigid plastic mats.
By pinning or otherwise mechanically clamping, bolting, screwing or otherwise affixing the plastic mats to the top surface of the scale platform, the mats cannot come loose or curl upwardly around their edges as is the case with conventional flexible rubber mats which are glued to the scale platform. Moreover, by layering the relatively rigid plastic mats on top of the sheet metal scale platform, the load bearing capacity and strength of the platform is significantly increased.
An important feature of the invention is the use of a plastic material known as fiber filled polyester thermoset plastic (FFP) to mold rigid, dimensionally stable scale mats for mounting to the platforms of household weigh scales. By using FFP, impact and cosmetic issues associated with other molded plastic materials are reduced or eliminated. For example, sturdy anchor posts for mounting the mats to the scale can be molded from FFP. These molded posts or pegs will not break off under rugged use, and unsightly depressions or similar sink holes typically formed over such posts can be eliminated through the use of FFP.
The superior mechanical properties of FFP include high strength represented by a flex modulus of over one million pounds per square inch. Moreover, FFP can be molded with various textures and colors that closely simulate the look, weight and feel of natural materials to an extent not presently feasible using conventional injection molded plastic, vinyl or rubber materials.
A particular advantage of using FFP to produce scale mats is the ability to closely replicate such xe2x80x9cnaturalxe2x80x9d materials as marble, granite, stone, brick, limestone and other hard materials.
The structural properties and rigidity of FFP strengthen and rigidify an underlying scale platform so as to promote accuracy and repeatability in weighing weights over 250 pounds. At these heavier weights, the rigidity of the scale platform becomes an important factor in scale accuracy.
In summary, the present invention is directed to a body weigh scale having a foot supporting platform mat that is formed of a polymeric, decorative material that is sufficiently rigid so that it may be produced relatively thin, and yet not significantly deflect under load. Moreover, the polymeric, decorative material provides an attractive surface after molding. To this end, the body weigh scale platform incorporates a fiber-filled, polyester thermosetting polymer material that has extremely low shrinkage rates so that the outer pattern and shape of the scale mat is not affected by the forming of very thin cross sections adjacent to thick cross-sections such as required for forming mounting members on the mat. The rigidity of the fiber-filled, polyester thermosetting polymer material provides sufficient structural support for operation of the thin foot support platform mat and without significant deflection of the material.
The body weigh scale foot support platform mat may be formed from a fiber-filled, polyester thermoset material using a variety of thermosetting polymer formation methods. As examples, the body weigh scale mat may be formed using compression, transfer, or stuffer injection molding. Injection molding may be performed using a reverse inverted temperature process, which involves cold barrel injecting into a hot mold.
By using the fiber-filled, polyester thermosetting polymer material, there is significant molding flexibility for the load-receiving platform mat of the body weigh scale. For example, mounting members such as pegs or posts may be formed integral with the load receiving platform mat for mounting the mat to the platform without weakening the structure or causing color distortion, surface sinks, visual level changes, or warpage.
The strength of the fiber-filled, polyester thermosetting polymer material permits the body weigh scale mat to have a profile that is thin and lightweight. Also, because the fiber-filled, polyester thermosetting polymer material has a low shrink rate, an aesthetically-pleasing decorative surface may be provided.